feat(agent): support user-initiated cancel for in-flight agent runs

docs/en/cli/general.mdx

@@ -25,6 +25,14 @@ View current session and service status, including process info, model configura
 /status
 ```
 
+## cancel
+
+Abort the agent task currently running in this session. When the agent is busy with a long task (e.g. multi-turn tool calls or a long streaming response), send `/cancel` and the agent will stop before the next tool execution. Available across all channels — Web, WeChat, WeCom, Feishu, etc.
+
+```text
+/cancel
+```
+
 ## config
 
 View or modify runtime configuration. Changes take effect immediately without restarting.

docs/en/cli/index.mdx

@@ -57,6 +57,7 @@ In the Web console or any connected channel, type `/` to see command suggestions
 | --- | --- |
 | `/help` | Show command help |
 | `/status` | View service status and configuration |
+| `/cancel` | Abort the currently running agent task |
 | `/config` | View or modify runtime configuration |
 | `/skill` | Manage skills (install, uninstall, enable, disable, etc.) |
 | `/memory dream [N]` | Manually trigger memory distillation (default 3 days, max 30) |
@@ -80,6 +81,7 @@ In the Web console or any connected channel, type `/` to see command suggestions
 | version | ✓ | ✓ |
 | status | ✓ | ✓ |
 | logs | ✓ | ✓ |
+| cancel | ✗ | ✓ |
 | config | ✗ | ✓ |
 | context | — | ✓ |
 | memory (subcommands) | ✗ | ✓ |